From 9f557cd8073104b39528794d44e129331ded649f Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 3 Feb 2010 08:27:22 -0500 Subject: [PATCH] NFS: Fix an Oops when truncating a file The VM/VFS does not allow mapping->a_ops->invalidatepage() to fail. Unfortunately, nfs_wb_page_cancel() may fail if a fatal signal occurs. Since the NFS code assumes that the page stays mapped for as long as the writeback is active, we can end up Oopsing (among other things). The only safe fix here is to convert nfs_wait_on_request(), so as to make it uninterruptible (as is already the case with wait_on_page_writeback()). Signed-off-by: Trond Myklebust Cc: stable@kernel.org --- fs/nfs/pagelist.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index e2975939126a..a12c45b65dd4 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -176,6 +176,12 @@ void nfs_release_request(struct nfs_page *req) kref_put(&req->wb_kref, nfs_free_request); } +static int nfs_wait_bit_uninterruptible(void *word) +{ + io_schedule(); + return 0; +} + /** * nfs_wait_on_request - Wait for a request to complete. * @req: request to wait upon. @@ -186,14 +192,9 @@ void nfs_release_request(struct nfs_page *req) int nfs_wait_on_request(struct nfs_page *req) { - int ret = 0; - - if (!test_bit(PG_BUSY, &req->wb_flags)) - goto out; - ret = out_of_line_wait_on_bit(&req->wb_flags, PG_BUSY, - nfs_wait_bit_killable, TASK_KILLABLE); -out: - return ret; + return wait_on_bit(&req->wb_flags, PG_BUSY, + nfs_wait_bit_uninterruptible, + TASK_UNINTERRUPTIBLE); } /**